Side gusseted paper bags have been commercially made for many years with openings that permit bag charging or filling. But these bags are quite costly, not only because of the additional materials needed about the bag filling opening, but also because of the labor and time to close and seal the bag.
One of the problems with fillable bags is the entrapment of air during the filling process which promotes poor filling and other problems.
The following patents were found in a preliminary patentability search:
U.S. patentsInventorU.S. Pat. No.Issue DateHarvey3,276,670Jul. 27, 1964Piazze3,618,478Nov. 9, 1971Benoit4,571,235Feb. 18, 1986Benoit4,655,737Apr. 7, 1987Roen, et al.4,717,262Jan. 5, 1988Humphrey4,764,030Aug. 16, 1988Benoit4,816,104Mar. 28, 1989Olesen4,881,825Nov. 21, 1989Beer4,913,561Apr. 3, 1990Gelbard4,943,167Jul. 24, 1990Mundus4,959,114Sep. 25, 1990Wood5,165,799Nov. 24, 1992Gebhardt5,676,467Oct. 14, 1997Schoeler5,862,652Jan. 26, 1999Daniels, et al.Re.36,876Sep. 19, 2000Beer6,213,645Apr. 10, 2001Angless6,254,520Jul. 3, 2001